Most insect larvae—grubs—can be found in the earth quite close to the surface. When our ancestors dug up the soil and removed rocks and roots to plant their seeds, they introduced the expression “grubbing up” from the old Germanic grubian, meaning “to dig up.” The diggers also got quite dirty, or grubby, from the grubbing. So how does this lead to food? One theory is that the slang word grub comes from watching the swarms of birds that followed the plough and picked up the juicy grubs. Another theory is that our distant ancestors actually collected the grubs for food
As for the word nosh, this is a Yiddish word that comes from the old Germanic word nascen, meaning “to nibble.” It only became popular in the 1950s and will probably soon die out, leaving the ancient word grub to act as a noun, a verb, an adjective, and curiously connected to our food.